For example, patent document 1 discloses this type of a heat dissipation device. The heat dissipation device of patent document 1 is formed by baking a lamination in which a plurality of ceramic sheets are stacked. The ceramic sheets include a ceramic sheet having a plurality of slits, which are elements of a coolant passage, and a ceramic sheet having a communication passage that communicates the coolant passage and the exterior. A metal plate to which a semiconductor element is coupled is joined with a heat dissipation device to form a semiconductor device. Heat is transmitted from the semiconductor element to the heat dissipation device through the metal plate and dissipated to the coolant flowing through the coolant passage. This cools the semiconductor element.